The potential impact of Anopheles stephensi establishment on the transmission of Plasmodium falciparum in Ethiopia and prospective control measures
Anopheles stephensi, the primary urban malaria vector in Asia, was first detected in Africa during 2012 in Djibouti and was subsequently identified in Ethiopia in 2016, and later in Sudan and Somalia. In Djibouti, malaria cases have increased 30-fold from 2012 to 2019 though the impact in the wider region remains unclear. A mechanistic model of malaria transmission was used to estimate the increase in vector density required to explain the trends in malaria cases seen in Djibouti. Applying this vector density to Ethiopia, we assess the potential impact of An. stephensi establishment on Plasmodium falciparum transmission, accounting for pre-existing transmission and control interventions. We estimate that annual P. falciparum malaria cases could increase by 50% (95% CI 14-90) if no additional interventions are implemented. Substantial heterogeneity across the country is predicted and large increases in vector control interventions could be needed to prevent a major public health emergency.